1. IAC 360°
15-12-2015
12.43pm

2. Great teachers – All this is their work .
I am just the reader of their books .
Prof. Paolo castelnuovo
Prof. Aldo Stamm Prof. Mario Sanna
Prof. Magnan

3. For Other powerpoint presentatioins
of
“ Skull base 360° ”
I will update continuosly with date tag at the end as I am
getting more & more information
click
www.skullbase360.in
- you have to login to slideshare.net with Facebook
account for downloading.

4. Bottle neck concept – junction of labyrinthine & internal
auditory canal facial nerve is narrow [ bottle neck ]

6. From CP angle book – see other
photos – fig 9

7. From mario sanna paraganglioma
book
Degree of bone removal
required in various
approaches. POST., posterior;
ANT., anterior; F, facial nerve.

8. FN & SVN converge as they pass toward the fundus , while the CN & IVN can
be seen diverging from each other as they pass laterally to the fundus - ---
Basal turn of cochlea pushing away IVN from CN
See the cochlea in below photo

9. 7up- 7th is above
Coca cola – cochlear n. is cola[=lower]

11. Translabyrinthine Transpetrous (
= Transapical )

12. The Enlarged Translabyrinthine Approach with Transpetrous ( =
Transapical ) Extension
Schematic drawings showing the amount of bone removal
around the internal auditory canal in the different variants of the
translabyrinthine approach. Note that in the transapical modification the
exposure is 320° and about 360° in types I and II, respectively. Abbreviations
as in Fig. 5.1. cn, cranial nerve; CN, cochlear nerve; FN, facial nerve;
IV, inferior vestibular nerve; SV, superior vestibular nerve.

13. (Right ear) Diagram of the internal auditory canal near the fundus.
The superior ampullary nerve (AN) is shown overlapping the superior vestibular
nerve (SVN). CN, cochlear nerve; FN, facial nerve; HC, horizontal crest; IVN,
inferior vestibular nerve; VC, vertical crest (Bill’s bar).

14. identify the superior
ampullary nerve first and then find the facial nerve
(F) after eliminating this nerve and the superior
vestibular nerve (Vs).

15. Drilling inferior to the right
internal auditory canal (IAC).
Further extensive drilling inferior to the internal auditory
canal (IAC) toward the petrous apex.

16. Extensive bone removal inferior and
superior to the internal auditory
canal (IAC). Bone superior to the
canal (*) is still to be removed.
The whole contents of the internal
auditory canal (IAC) are pushed
inferiorly to allow removal of the
remaining bone (*) superior to the
canal.

17. The whole contents of the canal are
displaced inferiorly to show the extent
of bone removal. The anterior wall of
the canal can also be drilled if needed.
Schematic drawing showing the technique and
extent of bone removal in the type I (green
line) and type II (red line) transapical
extension. F, facial nerve; C, cochlear nerve;
Vs, superior vestibular nerve; Vi, inferior
vestibular nerve.

18. Schematic drawing showing the technique and extent of bone removal in the type I
(green line) and type II (red line) transapical extension. F, facial nerve; C, cochlear
nerve; Vs, superior vestibular nerve; Vi, inferior vestibular nerve.

19. General view of the structures in the
cerebellopontine angle
after opening the dura. Note the enhanced
exposure of the angle and
the excellent exposure of the trigeminal
nerve (V).
The trigeminal nerve (V) is
pushed superiorly. The basilar
artery (BA) in the prepontine
cistern can be seen well.

21. With more traction of the tentorium, a panoramic view of the
structures in the angle is available. The trochlear nerve (IV) is
seen before piercing the tentorium to gain access to the middle
fossa.

22. (Left ear) Cadaveric dissection showing the intra-
canalicular structures.
Note the AICA runs between the facial nerve and the
cochlear nerve
in this case. FN(m), mastoid segment of the facial
nerve; JB, jugular bulb; SS,
sigmoid sinus; MFD, middle fossa dura; AICA,
anterior inferior cerebellar
artery; CN, cochlear nerve; FN, intracanalicular facial
nerve; *, the anterior
wall of the internal auditory canal.
(Left ear) Superior surgical field of enlarged
translabyrinthine approach
to the CPA. The trochlear nerve (IV);
trigeminal nerve (V) and superior
cerebellar artery (SCA) can be observed. AICA,
anterior inferior cerebellar
artery; FN, facial nerve; FN(m), mastoid
segment of the facial nerve; JB, jugular
bulb; SS, sigmoid sinus.

23. Mohnish grover Cochlear implant
radiology lines

24. Middle cranial fossa approach

26. For Other powerpoint presentatioins
of
“ Skull base 360° ”
I will update continuosly with date tag at the end as I am
getting more & more information
click
www.skullbase360.in
- you have to login to slideshare.net with Facebook
account for downloading.